1. Field of the Invention
The present invention relates to semiconductor manufacturing process, and more particularly to a method for improving the precision when removing the fin structures.
2. Description of the Prior Art
With the trend in the industry being towards scaling down the size of the metal oxide semiconductor transistors (MOS), the three-dimensional or non-planar transistor technology, such as the fin field effect transistor technology (Fin FET), has been developed to replace planar MOS transistors.
However, as the size of the FETs shrink, the electrical and physical requirements in each part of the multi-gate FET become critical, like the sizes and shapes of the fin-shaped structures and the spacing between each fin-shaped structure for example. Thus, how to reach standard requirements and overcome the physical limitations has become an important issue in the industry of the FETs.
In conventional processes, if a plurality of fin structures is disposed on a substrate, and the interval between each fin structure is small, when a photo-etching process is performed only once to remove some fin structures, since the density of fin structures between different regions (including the isolated region and the dense region) on the substrate is different, a precise positioning process is needed to etch some fin structures, so as to keep the required fin structures, which requires additional effort and time.